1. Field of the Invention
The present invention provides a display apparatus, and more particularly, to a display apparatus for displaying multiple images of viewing angles.
2. Descriptions of the Related Art
To obtain more vivid and realistic images, corresponding displaying technologies have been developed in succession over recent years to satisfy the viewers' demands. In contrast to early-stage flat panel display mainly focuses on the improvement of the resolution and colors, while recent years the three-dimensional (3D) display apparatuses' goal is to provide the viewers with a vivid stereoscopic displaying effect.
The stereoscopic displaying effect is achieved primarily by feeding different viewing angles of an object to the left and right eyes respectively. According to the vision characteristics of human eyes, when the left and right eyes receive two images with the same image contents but different parallaxes simultaneously, the 3D image of an object with a sense of level and depth will be perceived by the viewer.
In practice, 3D images are generally appreciated either by the use of glasses or by viewing the naked eye; technical developments over recent years have focused on the latter. Furthermore, when viewed with the naked eye, the images could be time multiplex or spatial multiplex method. The following gives a brief introduction of the two types.
FIG. 1 is a schematic view of a conventional projection-type stereoscopic display apparatus 1 adopting a spatial multiplex mode. As shown, the stereoscopic display apparatus 1 that adopts the spatial multiplex mode comprises a plurality of strip-like light sources 11 disposed adjacent to each other, a Fresnel lens 12 and a liquid crystal display (LCD) panel 13. The strip-like light sources 11 each provide a light beam to the Fresnel lens 12 sequentially. The light beam is focused by the Fresnel lens 12 in a planar manner and then imaged onto the LCD panel 13. After imaging onto the LCD panel 13 the image is projected onto a corresponding viewing zone. However, because one light source can only provide one viewing angle in the aforesaid stereoscopic image displaying technology adopting the spatial multiplex mode, the number of viewing angles that can be provided is limited to the capacity of the projector, and the disposition and arrangement of the light sources within the projector. Consequently, with the limitation of the light source, the resolution of the projector is hard to improve.
FIG. 2 is a schematic view of another conventional projection-type stereoscopic display apparatus 2 adopting the time multiplex mode. As shown, the display apparatus 2 comprises a light source 21, a polarizer 23, a rotary polygonal mirror 25, a panel 27 and a plurality of optical components 29. The light source 21 generates a light beam that is polarized by the polarizer 23 and then reflected by the rotary polygonal mirror 25 onto the panel 27 for imaging, which produces a scanning-like effect. Then, the optical components 29 project the images of different viewing angles to the different viewing zones according to a time sequence. More specifically, the light source 21 generates a first viewing angle image, a second viewing angle image, a third viewing angle image and a fourth viewing angle image onto adjacent different viewing zones of the panel 27 in different sequences. However, the projection-type stereoscopic display apparatus requires a rotary polygonal mirror 25 to realize the above said results. In addition, the rotary polygonal mirror 25 mostly functions mechanically, so considerable noises are produced due to the friction. Moreover, with the increasing demand of improved resolution, more viewing angles are to be provided, thereby, the rotation speed of the rotary polygonal mirror 25 must be increased, making the aforesaid shortcoming more prominent.
Therefore, there are still shortcomings and problems to be overcome either for the spatial or time multiplex method. Accordingly, it is highly desirable in the art to provide a stereoscopic display apparatus with advantages such as low costs, simplified optical configurations and a high resolution without the above said shortcomings and problems.